Method of producing a hollow metal member and an electroforming apparatus for performing the method

ABSTRACT

A method of producing a hollow metal member and an apparatus for producing the same wherein a hollow metal member has uniform thickness of the electrodeposited metal material on the core wires, uniform outer diameter and high accuracy of roundness and coaxiality. The method of producing a hollow metal member according to the present invention comprises the steps of: holding a conductive core wire as a material to be electrodeposited and one of an electrodeposit metal material and a metallic mesh basket for accommodating the electrodeposit metal material in a state horizontally opposed from each other; connecting a cathode of a power source to at least both end portions of the core wire; connecting an anode of the power source to at least both end portions of one of the electrodeposit metal material and the metallic mesh wire basket for accommodating the electrodeposit metal material; immersing one of the electrodeposit metal material and the metallic mesh basket and the core wire in an electrolytic cell charged with electrolytic solution; depositing the electrodeposit metal material on a surface of the core wire which is rotated in the electrolytic cell in a state of applying an electric power by means of electroforming to form an electroformed product; and removing the core wire from the electroformed product having a predetermined thickness.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method of producing a hollowmetal member as narrow tubular metal member through electroforming andan electroforming apparatus for performing the method. In particular,the present invention relates to a technique for producing a ferrulemade of metal, which is used for connecting optical fibers or forconnecting an optical fiber and an optical device with each other.

[0003] 2. Description of the Invention

[0004] A ferrule, as an important component in the opticalcommunication, has a hollow configuration as shown in FIG. 7 and has alength L of about 10 mm, an outer diameter D of 1.25 to 2.5 mm and aninner diameter d of 0.126 mm corresponding to the standard of theoptical fiber of which outer diameter is 0.125 mm.

[0005] Conventionally, a ferrule made from zirconia has been dominantlyused, which is complicated in the production process and the ferrulewith high dimensional accuracy cannot be efficiently produced. For thisreason, in recent years, a ferrule made of metal produced byelectroforming has been proposed.

[0006] As an example of the basic technique of a method of producing apipe-shaped metal member through electroforming, the Japanese laid-openpatent publication No. 11-193485 discloses a method of producing afine-hole tube.

[0007]FIG. 8 shows a schematic view for explaining a conventionalelectroforming apparatus for producing a hollow metal member as a narrowtubular metal member. An electrolytic cell 1 is filled with anelectrolytic solution 2. A metallic mesh basket 4 for accommodatingelectrodeposit metal material (electrolytic deposition of metal), whichis connected to an anode of a power source 3. A plurality of core wires6 as materials to be electrodeposited is provided in a holder 5. Arotation shaft 7 is fixed to the holder 5. A motor 8 is driven to rotatethe rotation shaft 7. A cathode of the power source 3 is electricallyconnected to each of the core wires via the rotation shaft 7 and theholder 5.

[0008] The metallic mesh basket 4 for accommodating the electrodepositmetal material and core wires 6 are immersed in an electrolytic solutionsuch that the lower end portion of each of metallic mesh basket 4 andthe core wires are inserted toward the bottom portion of theelectrolytic cell 1. The electroforming is performed by applyingelectric power from the power source 3 to the metallic mesh basket 4 andeach of the core wires while rotating the holder 5.

[0009] In the conventional technique, after the electrodeposit metalmaterial is electrodeposited on the core wires 6 to a predeterminedthickness, the core wires 6 are removed from the electroformed productto obtain a metal member having a long through hole with the innerdiameter corresponding to the outer diameter of the core wires 6. Then,the metal member is cut into those having a predetermined length toobtain a hollow metal as a ferrule, for example, as shown in FIG. 7.

[0010] However, in the conventional technique, a hollow metal memberwith high dimensional accuracy cannot be obtained in practice, althoughthe conventional technique may be performed theoretically. In theconventional electroforming, when the core wires are used for producinga hollow metal member, the following problem arises. In the productobtained by electroforming process, the electrodeposited hollow metalmember having a desired roundness and coaxiality of the hollow portionwith respect to the outer circumference cannot be obtained. Especially,when the layer thickness of the electrodeposited metal material in theelectroformed product that the metal material is electrodeposited on thecore wires is not uniform, the outer circumference fluctuates. As aresult, the electroformed product with desired roundness, thickness andcoaxiality cannot be obtained. The problem cannot be easily solved inthe subsequent process.

[0011] Especially, high accuracy of roundness, thickness and coaxialityare required for the ferrule. For this reason, it is important to solvethe problem of non-uniformity of the thickness of the electrodepositedmetal material in view of productivity and yield. Naturally, it isrequired for each of the core wires when electroforming issimultaneously performed to a plurality of core wires.

[0012] When the electroforming is performed by the electroformingapparatus having the structure as shown in FIG. 8, in an extreme case,electroformed products 9 may be different in appearance in thelongitudinal and circumferential directions. The problem is all causedby non-uniform thickness of the electroformed product 9 formed by theelectroforming.

[0013] As described above, the problem of non-uniformity in outerdiameter of the electroformed product may be depend on the configurationof the metallic mesh basket 4 for accommodating metal material to beelectrodeposited, as disclosed in the Japanese laid-open patentpublication No. 2001-207286. However, in practice, this solution is notsufficient to solve the problem, since the electroformed products havenon-uniform thickness of the electrodeposited metal material as shown inFIG. 9.

SUMMARY OF THE INVENTION

[0014] The present invention has been made in consideration of theproblems involved in the conventional technique as described above, andthe objects of the present invention are to provide a method ofproducing a hollow metal member and an apparatus for producing the samewherein a hollow metal member has uniform thickness of theelectrodeposited metal material on the core wires, uniform outerdiameter and high accuracy of roundness and coaxiality.

[0015] To accomplish the above object, a method of producing a hollowmetal member according to the present invention comprises the steps ofholding a conductive core wire as a material to be electrodeposited andone of an electrodeposit metal material and a metallic mesh basket foraccommodating the electrodeposit metal material in a state horizontallyopposed from each other; connecting a cathode of a power source to atleast both end portions of the core wire; connecting an anode of thepower source to at least both end portions of one of the electrodepositmetal material and the metallic mesh wire basket for accommodating theelectrodeposit metal material; immersing one of the electrodeposit metalmaterial and the metallic mesh basket and the core wire in anelectrolytic cell charged with electrolytic solution; depositing theelectrodeposit metal material on a surface of the core wire which isrotated in the electrolytic cell in a state of applying an electricpower by means of electroforming to form an electroformed product; andremoving the core wire from the electroformed product having apredetermined thickness.

[0016] With the method of producing the hollow metal member, whenelectroforming is performed, each of the anode and the cathode of thepower source is electrically uniformly connected to the entire portionof the core wire and the metallic mesh basket for accommodating theelectrodeposit metal material, so that the electrical atmosphere forelectrodepositing of metal to the core wire is uniformly created in theentire portion of the core wire and the metallic mesh basket foraccommodating the electrodeposit metal material and a uniform thicknessof the metal is electrodeposited on the core wire. As a result, a hollowmetal member has a uniform outer diameter and high accuracy ofroundness, and therefore, when the core wire is removed, a hollow metalmember having a high accuracy of coaxiality is obtained.

[0017] Another method of producing a hollow metal member according tothe present invention comprises the steps of: installing a plurality ofelectrolytic cells; in one of the one electrolytic cells, holding aconductive core wire as a material to be electrodeposited and one of anelectrodeposit metal material and a metallic mesh basket foraccommodating the electrodeposit metal material in a state horizontallyopposed from each other, connecting a cathode of a power source to atleast both end portions of the core wire, connecting an anode of thepower source to at least both end portions of one of the electrodepositmetal material and the metallic mesh wire basket for accommodating theelectrodeposit metal material, immersing one of the electrodeposit metalmaterial and the metallic mesh basket and the core wire in anelectrolytic cell charged with electrolytic solution, and depositing theelectrodeposit metal material on a surface of the core wire which isrotated in the electrolytic cell in a state of applying an electricpower by means of electroforming; repeatedly performing theelectroforming in other electrolytic cells one after another until anelectroformed product has a predetermined thickness; and removing thecore wire from the electroformed product.

[0018] With this method, when electroforming is performed, each of theanode and the cathode of the power source is electrically uniformlyconnected to the entire portion of the core wire and the metallic meshbasket for accommodating the electrodeposit metal material, so that theelectrical atmosphere for electrodepositing of metal material to thecore wire is uniformly created in the entire portion of the core wireand the metallic mesh basket for accommodating the electrodeposit metalmaterial and a uniform thickness of the metal is electrodeposited on thecore wire, which causes outer diameter to be uniform. Further,electrodeposit metal material to the core wires so as to graduallyincrease the thickness of the metal material allows the outerconfiguration of the electrodeposited metal material to becomeconsiderably smooth without roughness. As a result, a hollow metalmember with higher accuracy of roundness, thickness and coaxiality isobtained.

[0019] In the above method of producing a hollow metal member inelectroforming in each of electrolytic cell, at least one of current orvoltage applying to at least one of the electrodeposit metal materialand the metallic mesh basket for accommodating the electrodeposit metalmaterial can be changed gradually from a low current or a low voltage.In addition to the above, in electroforming in each of electrolyticcell, at least one of current or voltage applying to the core wire maybe changed gradually from a low current or a low voltage. With thesemethods, electroforming conditions in each of the electrolytic cells arecontrolled, so that various kind of electroforming may be performed ineach of the electrolytic cell. As a result, it is possible to provide ahollow metal member in which electrodeposit metal material is formedsatisfactorily.

[0020] An electroforming apparatus according to the present inventioncomprises: an electrolytic cell charged with electrolytic solution; apower source; means for holding a conductive core wire as a material tobe electrodeposited and one of an electrodeposit metal material and ametallic mesh basket for accommodating the electrodeposit metal materialin a state horizontally opposed from each other; means for connecting acathode of the power source to at least both end portions of the corewire; means for connecting an anode of the power source to at least bothend portions of one of the electrodeposit metal material and themetallic mesh wire basket for accommodating the electrodeposit metalmaterial; means for moving one of the electrodeposit metal material andthe metallic mesh basket and the core wire in the electrolytic cell;means for rotating the core wire in the electrolytic cell in a state ofapplying electric power from the power source to deposit theelectrodeposit metal material on a surface of the core wire and form anelectroformed product; and means for removing the core wire from theelectroformed product having a predetermined thickness. With theelectroforming apparatus, the method of producing the follow metalmember is performed satisfactorily.

[0021] In the above electroforming apparatus, a plurality ofelectrolytic cells and means for transporting the core wire to theplurality of electrolytic cells one after another can be mounted; and ineach electrolytic cell, a conductive core wire as a material to beelectrodeposited and one of an electrodeposit metal material and ametallic mesh basket for accommodating the electrodeposit metal materialmay be held in a state horizontally opposed from each other, theelectrodeposit metal material may be deposited on a surface of the corewire which is rotated in the electrolytic cell in a state of applying anelectric power by means of electroforming to gradually increasethickness of the electrodeposit metal material on the surface of thecore wire. With this electroforming apparatus, the above method ofproducing the hollow metal member may be performed satisfactorily.

[0022] It is possible that the above electroforming apparatus furthercomprises; means for holding a plurality of core wires in a statehorizontally opposed to one of the electrodeposit metal material and themetallic mesh basket for accommodating the electrodeposit metalmaterial; and means for moving the core wire holding mean to each of theelectrolytic cells. With this construction, a plurality of core wirescan simultaneously be electrodeposited, which enhances the productivityof the hollow metal member.

[0023] In the afore-mentioned electroforming apparatuses,current/voltage controlling means may be provided to change a value ofat least one of a current and a voltage to be applied to theelectrodeposit metal material, the metallic mesh basket foraccommodating the electrodeposit metal material or the core wire. Withthis electroforming apparatus, the method of producing the follow metalmember can be performed satisfactorily.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in further detail withreference to the accompanying drawings wherein:

[0025]FIG. 1 is a side view including partially sectional view of anelectroforming apparatus according to an embodiment of the presentinvention,

[0026]FIG. 2 is a front view of an electrode connecting member accordingto the embodiment of the present invention;

[0027]FIG. 3 is a drawing for explaining a plan condition of theconstruction of a production line in the electroforming apparatusaccording to the embodiment of the present invention;

[0028]FIG. 4 is a drawing for explaining a front condition of theconstruction of the production line shown in FIG. 3;

[0029]FIG. 5 is a drawing for explaining a constructional relationbetween a metallic mesh basket for accommodating the electrodepositmetal material and core wires according to the embodiment of the presentinvention;

[0030]FIG. 6 is a drawing for explaining a condition where anelectrolytic solution is stirred in an electrolytic cell according tothe embodiment of the present invention;

[0031]FIG. 7 is a cross-sectional view for explaining the configurationand the size of an ordinary ferrule;

[0032]FIG. 8 shows the construction of a conventional electroformingapparatus used for producing a narrow tubular metal member;

[0033]FIG. 9 shows a perspective view for explaining problems inelectroformed products produced in a conventional electroformingapparatus; and

[0034]FIG. 10 is a drawing for explaining problems caused by aconventional electroforming.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0035] The present invention will be described in detail with referenceto the accompanying drawings.

[0036] The inventor of the present invention has studied the problems ofnon-uniform thickness in outer diameter of the electrodeposited metalmaterial produced by electroforming (electrolytic deposition) for manyyears and repeatedly conducted experimental tests and found variousfactors for causing non-uniform thickness of the electrodeposited metalmaterial on the core wires. Especially, it is found that the method ofapplying an electric power to a core wire and a metallic mesh basket foraccommodating electrodeposit metal material and the condition forelectrodeposition of the metal material on the core wires causenon-uniformity in the electrodeposited metal material. The metallic meshbasket for accommodating the electrodeposit metal material may be usedas a single electrodeposit metal material. Accordingly, hereinafter, theconcept of the metallic mesh basket for accommodating the electrodepositmetal material includes a single electrodeposit metal material.

[0037] When electroforming is performed to core wires 6 in aconventional electroforming apparatus as shown in FIG. 8, a metallicmesh basket 4 for accommodating electrodeposit metal material and thecore wires 6 are placed in parallel with each other in the verticaldirection with respect to the bottom portion of an electrolytic cell. Inthis state, electroforming is performed by connecting an anode of apower source to only one end of the metallic mesh basket foraccommodating the electrodeposit metal material and connecting a cathodeof the power source to only one end of the core wires. As a result, thefollowing problems arises:

[0038] A The metallic mesh basket 4 for accommodating the electrodepositmetal material and the core wires 6 are long, so that a current/voltage(electric field) is not uniformly applied from one end to the other:

[0039] B When the distance between the metallic mesh basket 4 foraccommodating the electrodeposit metal material and the core wires 6 islong, the electrodeposite metal material electrically deposited from themetallic mesh basket 4 for accommodating the electrodeposit metalmaterial is moved in non-uniform state as shown by arrows in FIG. 10,which may be influenced by gravity, together with the cause as describedin the above A It is also one factor for non-uniform electrodeposion;and

[0040] C. The electroforming is continuously performed in the sameelectrolytic cell 1 in the state as described above for a long time, sothat delicate changes in the electroforming condition may occur, even ifvarious adjustments or controls are made.

[0041] In view of the above-mentioned matters, further consideration hasbeen made and various experimental tests have been repeatedly conducted.As a result, it is found that when the method of producing a hollowmetal member in the following electroforming apparatus is adopted, ahollow metal member having a high dimensional accuracy of a hollow metalmember having fine hole to sufficiently meet to the requirement for aferrule can be produced. The electroforming apparatus is constructed asfollows:

[0042] A. To at least both ends portions of each of the long sizedmetallic mesh basket for accommodating the electrodeposit metal materialand the long sized core wires, proper electrodes are connected;

[0043] B. The metallic mesh basket for accommodating the electrodepositmetal material and the core wires are placed in a state horizontallyopposed from each other in an electrolytic cell; and

[0044] C. The core wires are moved to a plurality of electrolytic cellsand in each electrolytic cell, electroforming is performed and theelectrodeposit metal material is formed on the core wires so as to bemade gradually thicker.

[0045] At least one of the above mentioned matters allows a metallichollow tubular member with a desirable high accuracy to be obtained.

[0046]FIG. 1 shows a side view including partially sectional view of anelectroforming apparatus according to an embodiment of the presentinvention. In this figure, reference numeral 11 denotes an electrolyticcell filled with an electrolytic solution 12. Reference numeral 13denotes a power source and 14, a metallic mesh basket in the form ofreticular cylinder or square for accommodating an electrodeposit metalmaterial. The metallic mesh basked 14 is connected to an anode of thepower source 13 at both ends portions and about the central portion andaccommodates an electrodeposit metal material. Reference numeral 15 iscore wires to be electrodeposited, which may be made from wire materialsuch as stainless, non-metallic material, resinous material plated withmetal by electroless plating, fibrous material. Reference numeral 16denotes chuck members provided with the core wire 15 having both endsenclosed therein. Reference numeral 17 denote a holder as a support jigwhich is placed so as to cover the upper portion of the electrolyticcell 11 The holder 17 having suspended portions 17 a by which the chuckmembers are rotatably supported allows a plurality of core wires 15 tobe supported. The holder 17 is driven to lower by a moving means, whichwill be described later, to immerse the core wires 15 in theelectrolytic solution 12 in the electrolytic cell 11, and the holder 17is driven upwardly to take out the core wires 15 from the electrolyticcell 11. Further, the holder 17 is driven to allow a back and forthmotion (in a direction vertical to the surface of the paper on whichFIG. 1 is illustrated) of the core wires 15 in the electrolytic cell 11to stir the electrolytic solution 12.

[0047] Further, reference numeral 18 denotes a rotation shaft which isconnected to the chuck members 16 to transmit the driving force forrotating the core wires 15 in the circumferential direction. Referencenumeral 19 denotes a driving gear fixed to the rotation shaft 18.Reference numeral 20 denotes a worm gear for rotating the driving gear19, and 21, a motor for driving the worm gear 20 via a belt 22.

[0048] A plurality of cap electrodes 23 is provided at one end portionof the chuck member 16, as shown in the left side in FIG. 1 and at theouter end portion of the rotation shaft 18, as shown in the right sidein FIG. 1. As illustrated in FIG. 2, the cap electrodes 23 are providedon an electrode connecting member 24 and electrically connected tocathodes of the power source 13 via a common electrode 25, as will bedescribed later.

[0049]FIG. 3 is a drawing for explaining a plan condition of theconstruction of a production line in the electroforming apparatusaccording to the embodiment of the present invention. FIG. 4 is adrawing for explaining a front condition of the construction of theproduction line shown in FIG. 3. A portion 26 consisting of a pluralityof electrolytic cells 11 is provided. At an upper stream of theproduction line as shown in left side in FIGS. 3 and 4, a first washingportion 27 consisting of a plurality of cells for washing the core wires15 before electroforming are provided and at an lower stream of theline, a second washing portion 28 consisting of a plurality of cells forwashing the core wires 15 after electroforming.

[0050] Further, reference numeral 29 denotes moving means whichcomprises a means for moving the holder 17 vertically to the portion 26,the first washing portion 27 and the second washing portion 28 to takein or out the core wires in each cells. The moving means 29 furthercomprises a moving means for moving the holder 17 to each of the cellsand a horizontally moving means for allowing a back and forth motion ofthe holder 17 (right and left motion in FIG. 4) to stir the electrolyticsolution 12 in a state which the core wires 15 are immersed. Referencenumeral 30 denotes a motion control means for controlling the movingmeans 29, and 31, a current/voltage control means which comprises acomputer, for instance, to variably control at least one of the valuesof a current or voltage from the power source 13 applied to the metallicmesh basket 14 for accommodating the electrodeposit metal material andthe core wires 15 in each of the electrolytic cells. In this case, thevariable control may be performed to at least one of the metallic meshbasket 14 and the core wires 15.

[0051] As described above, the holder 17 is movable to each of thecells. For this reason, as shown in FIGS. 1 and 2, the cathode of thepower source is electrically connected to the common electrode 25 in theelectrode connecting member 24 installing the cap electrode 23, so thatthe common electrode 25 is connected to a sliding electrode 32 installedat the ends of the holder 17 by an electric wire 33. The slidingelectrode 32 is electrically connected to the power source 13 viaelectrodes 34 each having a spring. As a result, when the holder 17moves, the electric power can be applied without disconnection of theelectrodes 34 from the sliding electrodes 32. Further, the electrodes 34having springs are served to perform the function to keep strengthagainst chemical tensile stress in electroforming (electrolyticdisposition).

[0052] In the construction according to the embodiment of the presentinvention as described above, the anodes of the power source 13 areelectrically connected to at least both ends portions of the metallicmesh basket 14 for accommodating the electrodeposit metal material, (itmay be considered that the cathode is electrically connected to thosesuch as a central portion, except for the both ends portions of the corewire 15, if it is permitted mechanically), and the cathodes of the powersource 13 are electrically connected to the both ends of the core wires(in the core wires 15, the cathode is electrically connected to thosesuch as a central portion except the both ends portions, if it ispossible mechanically), so that the condition of the electric field inthe metallic mesh basket 14 for accommodating the electrodeposit metalmaterial and the core wires 15 each having long configuration may bemade uniformly from one end to the other. As a result, theelectrodeposite condition on the core wires 15 by electroforming is madeuniformly in the longitudinal direction, allowing the electroformedproduct to have an identical outer diameter in the whole length thereof.

[0053] Further, as shown in FIG. 1, the metallic mesh basket 14 foraccommodating the electrodeposit metal material and the core wires 15are placed in parallel with each other and in a state horizontallyopposed to in the electrolytic cell 11 and electroforming is performedwhile rotating the core wires 15, so that the electrodeposit metalmaterial may be uniformly electrodeposited on entire surface of the corewires 15 in the longitudinal direction, as compared with a conventionalapparatus of the kind.

[0054] Further, the metallic mesh basket 14 for accommodating theelectrodeposit metal material may be placed in a higher position thanthe core wires 15, in the electrolytic cell 11.

[0055] Further, the roundness of the electroformed products obtainedunder various conditions are measured and it is found that therelationship between the metallic mesh basket 14 for accommodating theelectrodeposit metal material and the core wires 15 is also preferablein the following construction.

[0056] As shown in Fig, 5, in the longitudinal direction of the metallicmesh basket 14 for accommodating the electrodeposit metal material, themetallic basket 14 is preferably constructed such that each diameter d₁,of the both end portions and the diameter d₂ of the central portion arein the ratios of about 1.3:1 and the metallic mesh basket 14 and thecore wires 15 are separated from each other by a spacing distance X ofabout 55 to 65 mm. Further, in practical electroforming, the spacingdistance is measured by using ultrasonic waves to continuously observethe spacing distance X and are controlled so as to be within apredetermined range. As a result, the perfect roundness of theelectroformed product can be enhanced.

[0057] Further, as shown in FIGS. 3 and 4, the core wires 15 are orderlymoved to a plurality of the electrolytic cells 11 by the moving controlmeans 30 and the value of the current or the voltage to be applied tothe metallic mesh basket 14 and the core wires 15 is variably controlledby means of the voltage/current control means 31 to start theelctroforming from the electrolytic cells set at a low current/a lowvoltage. Then, the electrodeposit metal material is formed on the corewires to be made thicker gradually, so that the electrodeposit metalmaterial is smoothly formed on the outer circumferential portion and hasa fine configuration without roughness. As a result, theelectrodeposited metal material on the core wires is uniformly made inthe longitudinal direction.

[0058] Further, when the current or voltage is variably controlled at alow current/a low voltage having a low current density, it is preferablethat the spacing distance X (gap) shown in FIG. 5 is made narrower andthe spacing distance X is made longer as the current density becomeshigher.

[0059] In the embodiment according to the present invention, as shown inFIG. 6, the core wires 15 is driven to rotate and to move horizontally(right and left reciprocating motion), while moving to anotherelectrolytic cell 11 in a state of being immersed in the electrolyticsolution. By this movement of the core wires, the electrolytic solution12 is stirred, which is important to surround the core wires with freshelectrolytic solution, and to make the electroforming conditionexcellently. Further, it is important to enhance the uniformity of theelectrodeposited metal material together with the current conditionwhich is kept constant in the metallic mesh basket 14 and the core wires15, as described above.

[0060] Further, reference numeral 35 in FIG. 6 denotes a pipe as a partof a circulating system capable of circulating of the electrolyticsolution 12 and changing into a fresh solution. For stirring theelectrolytic solution 12, various measures can be taken. For example,the metallic mesh basket 14 for accommodating the electrodeposit metalmaterial may be moved reciprocatively in the electrolytic cells 12.

[0061] As described above, the electroforming is performed in theproduction line as shown in FIGS. 3 and 4, and the electroformed producthaving a predetermined thickness is subjected to the washing process.Then, the core wires 15 are extracted or chemically removed from theelectroformed product or the core wire portions is subjected tomechanical process so as to have a predetermined diameter. As a result,a metal member with fine hole is obtained.

[0062] Further, with respect to the arrangement of the production line,L-shaped arrangement or U-shaped arrangement in each cells can beconsidered in addition to linear arrangement as shown in FIG. 3.

[0063] In removing the core wires, since the metal material may beuniformly electrodeposited on the entire surface and length of the corewires 15 and the obtained electroformed product is uniform in outerdiameter, the metal member from which the portion corresponding to thecore wire 15 is removed is a hollow metal member with high accuracy ofroundness, thickness and coaxiality. Further, the electrodeposit metalmaterial is gradually electrodeposited on the core wires to increase thethickness, so that the circumferential configuration is very smooth andfine without roughness. As a result, a hollow metal member with higheraccuracy of roundness, thickness and coaxiality can be obtained.

[0064] For this reason, an excellent result can be obtained, which issuitable for the production of a product such as a ferrule for whichhigh accuracy of roundness, thickness and coaxiality are required. Forexample, the high accuracy of roundness and coaxiality of about ±1˜3 μmcan be obtained.

[0065] Further, in the production line as shown in FIGS. 3 and 4, whenthe value of the current/voltage to be applied to the metallic meshbasket 14 for accommodating the electrodeposit metal material and corewires 15 is variably controlled by a computer or the like to performelectroforming in each electrolytic cell, the electrolytic condition ineach electrolytic cells 11 can be varied. For this, the electrolyticcell 11, which is not used and vacant, is suitably selected to use andelectroforming is performed while moving the electrolytic cells from theselected electrolytic one to another, so that a desirable electroformedproduct can be produced. As a result, the production method according tothe present invention is advantageous in production efficiency andproduction cost, as compared with the conventional method in whichelectroforming is continuously performed until the electroformed producthas predetermined thickness in a single electrolytic cell.

[0066] As described above, with the method of producing a hollow metalmember and the electroforming apparatus according to the presentinvention, the metal material is electrodeposited on the core wires withuniform thickness by electroforming, the outer diameter of the obtainedelectroformed product is uniform in the entire surface and length,resulting in high accuracy of roundness. For this, the metal memberafter the core wires are removed is a hollow metal member with highaccuracy of thickness and coaxiality. As a result, a method of producinga hollow metal member and an electroforming apparatus, which aresuitable for the production of a product such as a ferrule for whichhigh accuracy of roundness, thickness and coaxiality are required, arerealized.

What is claimed is:
 1. A method of producing a hollow metal membercomprising the steps of: holding a conductive core wire as a material tobe electrodeposited and one of an electrodeposit metal material and ametallic mesh basket for accommodating the electrodeposit metal materialin a state horizontally opposed from each other; connecting a cathode ofa power source to at least both end portions of said core wire;connecting an anode of the power source to at least both end portions ofone of said electrodeposit metal material and said metallic mesh wirebasket for accommodating the electrodeposit metal material; immersingone of said electrodeposit metal material and said metallic mesh basketand said core wire in an electrolytic cell charged with electrolyticsolution; depositing said electrodeposit metal material on a surface ofsaid core wire which is rotated in the electrolytic cell in a state ofapplying an electric power by means of electroforming to form anelectroformed product; and removing said core wire from saidelectroformed product having a predetermined thickness.
 2. A method ofproducing a hollow metal member comprising the steps of: installing aplurality of electrolytic cells; in one of said one electrolytic cells,holding a conductive core wire as a material to be electrodeposited andone of an electrodeposit metal material and a metallic mesh basket foraccommodating the electrodeposit metal material in a state horizontallyopposed from each other, connecting a cathode of a power source to atleast both end portions of said core wire, connecting an anode of thepower source to at least both end portions of one of said electrodepositmetal material and said metallic mesh wire basket for accommodating theelectrodeposit metal material, immersing one of said electrodepositmetal material and said metallic mesh basket and said core wire in anelectrolytic cell charged with electrolytic solution, and depositingsaid electrodeposit metal material on a surface of said core wire whichis rotated in the electrolytic cell in a state of applying an electricpower by means of electroforming; repeatedly performing saidelectroforming in other electrolytic cells one after another until anelectroformed product has a predetermined thickness; and removing saidcore wire from said electroformed product.
 3. The method of producing ahollow metal member as claimed in claim 2, wherein in electroforming ineach of electrolytic cell, at least one of current or voltage applyingto at least one of said electrodeposit metal material and said metallicmesh basket for accommodating the electrodeposit metal material ischanged gradually from a low current or a low voltage.
 4. The method ofproducing a hollow metal member as claimed in claim 2, wherein inelectroforming in each of electrolytic cell, at least one of current orvoltage applying to said core wire is changed gradually from a lowcurrent or a low voltage.
 5. An electroforming apparatus comprising: anelectrolytic cell charged with electrolytic solution; a power source;means for holding a conductive core wire as a material to beelectrodeposited and one of an electrodeposit metal material and ametallic mesh basket for accommodating the electrodeposit metal materialin a state horizontally opposed from each other; means for connecting acathode of the power source to at least both end portions of said corewire; means for connecting an anode of the power source to at least bothend portions of one of said electrodeposit metal material and saidmetallic mesh wire basket for accommodating the electrodeposit metalmaterial; means for moving one of said electrodeposit metal material andsaid metallic mesh basket and said core wire in the electrolytic cell;means for rotating said core wire in the electrolytic cell in a state ofapplying electric power from the power source to deposit saidelectrodeposit metal material on a surface of said core wire and form anelectroformed product; and means for removing said core wire from saidelectroformed product having a predetermined thickness.
 6. Theelectroforming apparatus as claimed in claim 5, wherein a plurality ofelectrolytic cells and means for transporting said core wire to theplurality of electrolytic cells one after another are mounted; and ineach electrolytic cell, a conductive core wire as a material to beelectrodeposited and one of an electrodeposit metal material and ametallic mesh basket for accommodating the electrodeposit metal materialare held in a state horizontally opposed from each other, saidelectrodeposit metal material is deposited on a surface of said corewire which is rotated in the electrolytic cell in a state of applying anelectric power by means of electroforming to gradually increasethickness of said electrodeposit metal material on the surface of saidcore wire.
 7. The electroforming apparatus as claimed in claim 6 furthercomprising; means for holding a plurality of core wires in a statehorizontally opposed to one of said electrodeposit metal material andsaid metallic mesh basket for accommodating the electrodeposit metalmaterial; and means for moving said core wire holding mean to each ofsaid electrolytic cells.
 8. The electroforming apparatus as claimed inclaim 6, wherein current/voltage controlling means is provided to changea value of at least one of a current and a voltage to be applied to saidcore wire.
 9. The electroforming apparatus as claimed in claim 6,wherein current/voltage controlling means is provided to change a valueof at least one of a current and a voltage to be applied to one of saidelectrodeposit metal material and said metallic mesh basket foraccommodating the electrodeposit metal material.
 10. The electroformingapparatus as claimed in claim 7, wherein current/voltage controllingmeans is provided to change a value of at least one of a current and avoltage to be applied to one of said electrodeposit metal material andsaid metallic mesh basket for accommodating the electrodeposit metalmaterial.
 11. The electroforming apparatus as claimed in claim 7,wherein current/voltage controlling means is provided to change a valueof at least one of a current and a voltage to be applied to said corewire.